The purpose of this study is to determine if the etiology of Wasting Marmoset Syndrome (WMS) is related to zinc deficiency. The clinical symptoms of zinc deficiency and WMS are very similar. It has been determined that th S. mystax are very zinc deficient. The study will involve feeding two diets to several wasting S. mystax, one diet will be supplemented with zinc and the other will not be. Serum zinc titers and blood chemistries will be sampled of a regular basis. Tissues will be taken from tarmarins that die for zinc analysis. The S. mystax is an invaluable lab animal model for infectious disease study. However, in captivity, these tamarins are unable to breed and eventually die due to WMS. The fact that S. mystax are zinc deficient may provide an answer to the etiology of WMS.